Guarantee zmq-core has been loaded

Requiring `zmq` no longer loads it in >= v1.0.1

* jupyter-ioloop.el: Call `zmq-load` at top level

* jupyter-zmq-channel.el: Ditto.

Author: nnicandro

jupyter-ioloop.el

@@ -50,6 +50,7 @@
 
 (require 'jupyter-base)
 (require 'zmq)
+(eval-and-compile (zmq-load))
 (eval-when-compile (require 'subr-x))
 
 (defvar jupyter-ioloop-poller nil

jupyter-zmq-channel.el

@@ -36,6 +36,7 @@
 
 (require 'jupyter-messages)
 (require 'zmq)
+(eval-and-compile (zmq-load))
 (require 'jupyter-channel)
 (eval-when-compile (require 'subr-x))